RICHMOND — State Sen. Mark D. Obenshain said Monday he will not run for Virginia governor in 2017, a surprise move that helps clear the way for Ed Gillespie, who plans to seek the Republican nomination, according to three people close to the political strategist.

A gubernatorial run by Gillespie, a former chairman of the Republican National Committee who nearly unseated U.S. Sen. Mark R. Warner (D-Va.) last year, could give the Virginia GOP a much-needed boost as it struggles to rebound from a series of bruising statewide loses.

Gillespie, who worked in George W. Bush’s White House, has proved to be the rare candidate capable of uniting moderate Republicans and hard-core conservatives whose schism has cost the party every statewide election since 2009.

As a longtime strategist and prolific fundraiser, Gillespie could have an edge with Virginia voters who two years ago delivered the state’s highest office to the ultimate Democratic Party insider — Gov. Terry McAuliffe.

Some observers have speculated that the methodical Obenshain, though long considered the front-runner in the race for the GOP nomination, might not be the best messenger for a party trying to make a comeback. Gillespie, a veteran of the Sunday morning TV circuit, is seen as a stronger communicator and has shown the ability to energize the party in a swing state with an influx of Democrats in the Washington suburbs.

Obenshain (Rockingham), who narrowly lost the attorney general’s race in 2013, said the decision was his alone, and he was not forced off a run for the governor’s mansion by state or national party insiders.

“I spent a lot of time trying to make the assessment of whether I had another statewide campaign in me and, at the end of the day, I’m just content to focus on my service in the Senate,” Obenshain said in a phone interview with The Washington Post.

He added: “I was no way pressured out by anybody. Nobody called, nobody broke my knee caps or arms. It was purely a personal, political, family and business decision.”

For now, Gillespie is keeping mum on his plans, and no other Republicans have made their intentions known. Names often mentioned include former attorney Ken Cuccinelli II, who lost to McAuliffe; U.S. Rep. Rob Wittman; and state Sen. Jeffrey L. McWaters (R-Virginia Beach).

While supporters say Gillespie’s entry into the race could clear the field, others note the unpredictable nature of Republican politics in Virginia. That’s especially true if the party follows the recommendation of its governing board and holds a convention — day-long gatherings that tend to attract the most committed activists — instead of a state-run primary open to all.

Gillespie won the nomination for Senate at a convention, but he could have a tougher time if a tea party star jumps in.

“The list of Republicans running for governor of Virginia will be about as long as the list of Republicans running for president,” said Chris LaCivita, a longtime GOP strategist who ran Cuccinelli’s 2013 race.

Obenshain’s decision to bow out comes less than a month after the presumed front-runner on the Democratic side, Attorney General Mark R. Herring, delivered the equally shocking news that he wouldn’t seek his party’s nomination and instead endorsed Lt. Gov. Ralph Northam for governor.

Bob Holsworth, a principal of DecideSmart, a Richmond public policy consulting firm, said should Gillespie win the office, the keys to Virginia’s governor’s mansion would pass from a former Democratic National Committee chairman to a former RNC chairman.

“It reinforces how closely Virginia politics is linked to national politics,” he said. “This would be one more candidate that really begins as a national figure and then comes here.”

Indeed, both McAuliffe and Gillespie were raised in the Northeast and attended Catholic University before rising through national politics and settling in Fairfax County, where they have lived for decades. McAuliffe failed to secure the 2009 Democratic nomination for governor and Gillespie lost to Warner in his first race as the candidate in the spotlight.

Thanks to his strong showing last year, Gillespie, who developed Newt Gingrich’s “Contract With America” and helped found Crossroads GPS with Karl Rove, would be a prolific fundraiser who inspires donations from national groups.

“Ed Gillespie is a very effective leader and, if he chooses to run, would be a strong candidate for Virginia governor,” said Jon Thompson, a spokesman from the Republican Governors Association, which has poured millions into Virginia’s off-year gubernatorial races.

Obenshain could have been a more polarizing figure. As a candidate for attorney general, he promised to protect gun rights, to stand up to federal “overreach,” and resist the expansion of Obamacare, as well as emphasizing law-and-order issues such as cracking down on sex offenders, human traffickers and abusers of the elderly. He once sponsored — and later withdrew — a bill that would have required women to report a miscarriage to police.

But the son of Richard D. Obenshain, a GOP stalwart who died in a 1978 plane crash while campaigning for U.S. Senate, declined to rule out a future statewide bid.

Gillespie, a personal friend and political ally of Obenshain for years, said he would not have challenged the state senator for the nomination. As chairman of the Republican State Leadership Committee, he steered $2.8 million to Obenshain’s 2013 campaign, according to the Virginia Public Access Project.

“I know he gave his decision thoughtful, prayerful consideration. No matter what office he holds, Mark will continue to be one of our Commonwealth’s most effective servant leaders for years to come, which is a good thing for all who call Virginia home,” Gillespie said Monday on his Facebook page.

After his Senate race, Gillespie remained active in Virginia Republican politics, appearing with candidates running for everything from high-stakes state Senate races to local commonwealth’s attorney and county supervisors races.